Filament mounting for high power electron discharge devices



y 3, 1952 E SHO\NER 2,602,907

FILAMENT MOUNTING FOR HIGH POWER ELECTRON DISCHARGE DEVICES Filed Jan. 14. 1949 FIG.

INVENTOR By 'E.G. SHOWER ATTORNEY l atented July 8, 1952 asogpov FILAMENT MOUNTING FOR HIGH POWER aircrew mcee PEVIQES Edmund G. Shower, QuakbI'ZQWP: zPai, assigns! to B l Tele hone Lab a ies. nc rporates Ne 9r1a.- i a W i"..- N

errl wii lee e v 14, 194.9,. "serial ews 1 1 fi aims. 1

This invention relates to filament mountings for electron discharge devices and more particu: larly to filament mountings for high power .water or air-cooled electron discharge devices.

In some types of electron discharge devices, it is generally necessary for the multistrand fila.-. ment assembly to be'mounted under tension in order to prevent bowing and possible contact vof the filaments with adjacent elements. In most conventional constructions this is accomplished bysprings and bearings within-the high temperae ture-zone of the device. However, the spring and bearings thus located within the envelope are subjected to intense heat and bombardment effects from the filament and are frequently dam-r. aged thereby.

01 e e a o e of th venti n i to mpr ve fi a en mount s o electron dischar e defi es- M 16? S ecifi al y. ob e ts o t is in ention a e to pre en e an bomb rdmen fiects 13 s ch mou in t acil ta h m un in en i nSi nin or? mi lti' t e i fi s eiit and to exi i e a za f ar d m ntena ce .3 a. prescribed tension in such filarn One feature of the inventio' relates toaprese sure sensitive element or bellows arrangementfor tensioning the filament byatmospheric'pressure acting on bellows the el s a in "of bi e end or the device.

nether feature relates to the addition of a pressure means for altering the tension on the fi m I' S ll i @93 a o h r c P11 111? in o e be lo s A. further ea ur inv v h Pr is o o ear n memb ex na of t e ve e o positioning the standard which supports and tensions the filament assembly, where they are accessible for lubrication and far enough removed from the filament so as not to be afiected by heat and bombardment effects. w

=The invention and the features thereof will be more-fullyunderstood from a consideration of the embodiments illustrated-in the accompany ing drawings in which:

Fig. 1 is a view, partly elevational and partly sectional, of a water-cooled electron'idischargle device embodying features of this invention;

Fig. 2 is an enlarged perspective view of portions of-the filament assembly showing details of the mounting structurefor the multistrand file.- ments employed in the device of Fig. '1; s

Fig. 3 is an elevational view, partly in section, of amodification of the bellows arrangement as applied to the device of Fig. Lin-which asp ring member is provided within the'bellow's for alter *2 ing the tension exerted .on the multistr-and ment by atmospheric pressure .actinglon the-bole,

lows;

Rig. 41s an elevational .view, .partly section, of another modificationiof the bellows arrangement in .which the filamentstandard bearings are positioned withinitliecbellows and aispring meme her is arranged externally of :the bellows for altering the tension exerted .on --the multistrand filament :by, atmospheric .p'ressurei and Fig. :5 is a plan .view of the. device of g1 showing the arrangement .of ..terminals, filament standard and filament standard bearings on .thamounting-plate.

Referring'now to the drawings, I10; is .a .water: cooled high .vacuum discharge device in which a tubular anode Al and iiange l2, preferably .of copper, are joined, as by soldering with silver, to Water jacket .I 3. A-metallic sleeve or ring mem-z ber .14, preferably .of :Kovar, which .is an alloy of nickelyiron and cobalt, is plated with .pure gold to :facilitate the sealing thereto of -a glass .cylin; der 1:5 which forms part .of the enclosing .yessel of the device. A c'oldrolled steelring or insert [5 soldered between sleeve 14 and flange 4-2 .to provide an .eficient joint between the Kcivar and copper members of the leasing. Another .Kovar sleeve I1 is hermetically sealed to the opposite endiofthecylinder I 5 and joined-to a rigidclosure disc or base .plate 1.8, preferably of =Monel alloy, byia similar ring insert [9. A. cylindrical metallic sleeveoripartition member 20 is mounted inter; mediate the. anode -.I.l and water jacket .13 to form inlet and outlet chambers for .the cinema; tion of a cooling medium such .as (water. .in the device to dissipate .the' intense heat energy-gen; erated in the .anode during operation.

.The heavy base plate i8 is the main support: ing body for the grid .and filament assemblies. The grid comprises a plurality of metal support rods '2! which are arranged in .a circle .within the :tube, equidistant fromithe. cylindrical anode II, with the lower end of each rod 2l .welded to end plate or disc shield 22 and with the upper end of eaehrod 2i weldedto a flange 23. Aliencalgrid coil 24 is wound I around the support rods 21 continuously from one end to the other end thereof and is'welded to these support rods' ill at each point of contact therewith." The fiangje 2-3 is'attached to plate 18- by .a plurality of .screvis 25. A-guardringor shield 26 is also attachd to plate 18 by screws 25. Elie igrid' helix -24 thus electrically connected toplate 1 8 which forms-an external ring terminal.

The multistrand filament assembly includes a is shown in section in Fig. l. A metallic stud 3I, preferably of copper, is plated with pure gold to facilitate the sealing thereto of a glass cylinder 32 which forms part of the structure of terminal 30. Another gold plated copper sleeve 33 is hermetically sealed to the opposite end of the cylinder 32 and is joined to plate I8 by brazing it thereto. The upper end of a rod 34 is tightly fitted with a cavity 36 of stud 3 I. A metallic circular platform 36 is secured to the lower end of rod 34 by a screw 31.

Terminal 46 is constructed similar to terminal 30. A metallic stud 4I, preferably of copper, is plated with pure gold to facilitate the sealing thereto of the glass cylinder 43. Another gold plated copper sleeve 44 is hermetically sealed to the opposite end of cylinder 43 and is jointed to plate I8 by brazing it thereto. The upper end of rod 45 is tightly fitted in a cavity in stud M. A metallic circular platform 46 is secured to the lower end of rod 45 by a screw 41. V

The device shown in Fig. 1 has a plurality of terminals, which are arranged with alternate terminals connected to platforms 36, 46 respectively. In the tube illustrated there are three terminals attached to platform 36 and three attached to platform 46, arranged in a circle about the axis of tube I6, as shown in Fig. 5.

As shown in Fig. 2, platform 36 supports a plurality of filament support hooks 38 welded thereto at their upper ends in apertures 36. Hooks 36 extend through clearance holes 43 in platform 46. Platform 46 supports hooks 46 welded to it, at their upper ends in apertures 56. Hooks 38, 49 alternate in a circle around platforms 36, 46, the center of the circle lying on the vertical axis of device I6. There are the same number of hooks 38 as there are of hooks 46. They are used in pairs, each pair supporting one of a plurality of filament loops 66. The lower end of each filament loop 66 extends under the hooked ends GI, 62 of metallic support fingers 63, 64, respectively, which protrude from disk 66. Similar support fingers 65 are spaced in pairs around the periphery of metallic disk 66. Disk 66 is rigidly supported by insulating disk 61 which is attached to filament standard I6 by a washer 'II and screw I2 which threads into the end of filament standard 10. The upper ends of filament loops 66 are welded to hooks 38, 46. The upper end of filament standard I6 is guided in a vertical position by a sleeve bearing '53, which is brazed to terminal plate I8.

As shown in Fig. l, a bellows member 66 is attached to bearing I3 by brazing the upper edge 8| into a circular recess in the lower face of bearing I3. The bearing 13 has a vent 82 for maintaining atmospheric pressure within the bellows 80. A bushing 83 is brazed to the lower face of bellows 66. Filament standard 76 extends through and is welded to bushing 83 to form an airtight seal.

vThe operation of the filament mounting shown in Fig. l, is that the atmospheric pressure within bellows 66 forces the lower surface of bellows 86 downward. The filament standard I6 which is rigidly attached to bellows 60, applies this force to disk 61 which in turn forces disk 66 downward thus forcing the support fingers 63, 64, 65 downward. As the upper ends of the filament loops 66 are rigidly attached to platforms 36, 46, by means of hooks 38, 49, the downward force on the support fingers 63, 64, 65 tensions the filament loops 4 Fig. 3 illustrates another embodiment of the invention in which a helical spring 96 is positioned Within bellows 86 extending spirally around filament standard I6 between the lower face of bearing l3 and the upper face of the bottom of bellows 36. Spring 96 may be in compression or it may be extended. In the latter case it is rigidly attached to the lower surface of bearing 13 at its upper end and its lower end is rigidly attached to the upper face of the bottom of bellows 86.

In the embodiment of he invention shown in Fig. 3 the function of helical spring 96 within bellows 86 is to alter the tension exerted on the filament loops 66 by atmospheric pressure acting on the bellows 86. If spring 96 is placed in the bellows in compression, the tension on filament loops 66 by atmospheric pressure within bellows 86 is increased. If spring 66 is in tension between bearing 73 and the lower face of the bellows 86 the resulting tension on the filament loops 60 is less than would be caused by atmospheric pressure only.

Fig. 4 shows another embodiment in which a bearing I66 for filament standard 76 is brazed to plate I6 and extends inwardly within bellows 86 and a helical spring I6I extends around filament standard (6 between the upper face of bearing I66 and a collar I62 which is rigidly attached to the upper end of filament standard I6. Spring i6! may be in compression or it may be extended. In the latter case its upper end is rigidly attached to collar I62 and its lower end is rigidly attached to the upper surface of bearing I66. Bearing I66 has a vent I63 for maintaining atmospheric pressure within bellows 86.

In the embodiment of the invention shown in Fig. 4, the function of helical spring IOI is to alter the tension exerted on the filament loops 66 by atmospheric pressure acting on the bellows. If spring I6I is placed on filament standard 16 in compression, the tension on filament loops 60 by atmospheric pressure within bellows 66 is increased. If spring I6I is in tension between collar I62 and bearing I60 the resulting tension on filament loops 66 is less than would be caused by atmospheric pressure only.

A typical device which may embody this invention is disclosed in detail and claimed in the application of C. E. Fay and D. A. S. Hale, Serial No. 68,346, filed December 30, 1948, now Patent No. 2,534,548, issued December 19, 1950.

While this invention has been disclosed with reference to various specific embodiments, it is, of course, understood that other modifications may be devised by those skilled in the art without departing from the scope and spirit of the invention.

What is claimed is:

1. A filament mounting assembly comprising a closure having an opening on one end of the easing of an electronic discharge device, a standard extending through said closure, a filament supported by said standard, and a pressure responsive element carried by said closure for sealing said opening and attached to said standard to apply tension by atmospheric pressure to said filament.

2. A filament mounting assembly comprising a closure on one end of the casing of an electronic discharge device, a standard extending through said closure, a multistrand filament supported on said standard, bearing members on said closure engaging said standard, and a pressure responsive bellows supported by said closure and atshaft for supporting said filament whereby said filament is tensioned by atmospheric-pressure.

'4. A filament mounting assembly comprising. a closureononeend of the casing of anelectronic discharge device, a -sta'ndard extending. through said closure, a multistrand filamentssupporton said standard,'bearing members on said closure engaging said standard, a bellowsresponsive to atmospheric pressure supportedby said closure and attached to saidstanda-rd to apply tensionto said filament by atmospheric pressure, and means within said bellows to. alter the tension on said filament.

5. A filament mounting assembly comprising a closure on one end of the casin of an electronic discharge device, a standard'extending through said closure, a multistrand filament supported on said standard, bearing members on said closure engaging said standard, a bellows responsive to'atmcspheric pressure supported by saidclosure and attached to said standardto apply tension by atmospheric pressure to said filament, and a helical spring coaxially about said standard and having one end abutting against one of said bearing members and the opposite end abutting against said bellows.

6. A filament mounting assembly comprising a closure on one end of the casing of an electronic discharge device, a standard extending through said closure, a multistrand filament supported on said standard, bearing members on said closure engaging said standard, a pressure responsive bellows sup-ported by said closure and attached to sand standard to apply tension to said filament by atmospheric pressure, and a helical spring coaxially about said standard and extending between one of said bearing members and said bellows.

7. A filament mounting assembly comprising a closure on one end of the casing of an electronic discharge device, said closure having an aperture therein, a standard extending through said closure, a multistrand filament supported on said standard, bearing members on said closure engaging said standard, a bellows responsive to atmospheric pressure supported by said closure and attached to said standard to apply atmospheric pressure to tension said filament, and a helical spring coaxially about said standard in compression between the inner face of one of said bearing members and said bellows.

8. A filament mounting assembly comprising a closure on one end of the casing of an electronic discharge device, a standard extending through said closure, a multistrand filament supported on said standard, bearing members on said closure engaging said standard, a pressure responsive bellows support-ed by said closure and attached to said standard to apply atmospheric pressure to tension said filament, and means within said bellows to increase the tension applied to said filament by said bellows.

9. A filament mounting assembly comprising a closure on one end of the casing of an electronic discharge device, a standard extending through said closure, at multistrand filament supported on said standard, bearing members :on said closure lens gaging said standard, .-,a pressure responsive bellows supported by said closure andattached to said standard to .applyatmospheric pressure to tension said "filament, and-means within said bellows to decrease the tension applied :to said filamentby said bellows.

10. A filament mounting assembly comprising'a closure .on one end'of the casing of .a-nzelectronic discharge device, a standard extending through said closure, a multistrand filament supportedon said standard, a bea-ringmemberexternalzof said closure engaging said .standard, .a pressure re.- sponsive bellows supp'ortedby :said closure and attached to said standardto apply :tension-byat: mosphericpressure to said filament,.-and a helical spring .aroundsaid standard within isaid beilows in -.-cornpression. between :said closure and-the bottom: of said bellows.

'11. A' filament mounting assembly comprisinga closureon one endofwthe casingof-an electronic discharge device, a standard extending through said :closure, a multistrand filament supported on said standard, a bearing member external of said closureengaging'said standard, :a pressure responsive bellows supported by said standard. to applyatrnospheric pressure to tensionsaida-filament,-and'a helical spring around said standard within said bellows in tension between: said closureandthe-bottom of said'bellows.

12. A filament mounting assembly comprising a closure having an opening in one end of the cas- 1 ing of an electronic discharge device, a standard extending through said closure, a multistrand filament supported on said standard, a pressure responsive bellows supported by said closure and attached to said standard to apply atmospheric pressure to tension said filament, a bearing member attached to said closure and extending internally of said bellows and engaging said standard, a collar rigidly attached to the external end of said standard, and a helical spring around said standard external of said closure in compression between said collar and said closure.

13. A filament mounting assembly comprising a closure in one end of the casing of an electronic discharge device, a standard extending through said closure, a multistrand filament supported on said standard, a pressure responsive bellows supported by said closure and attached to said standard to apply tension by atmospheric pressure to said filament, a bearing member attached to said closure, extending internally of said bellows and engaging said standard, a collar rigidly attached to the external end of said standard, and a helical spring around said standard external of said closure in tension between said collar and said closure.

14. An electron discharge device comprising a sealed and evacuated envelope, said envelope including a bellows as part thereof with one side of said bellows exposed to the evacuated interior of the envelope and the other side exposed to the atmosphere at the exterior of the envelope, a cathode in said envelope, and means connecting the bellows and cathode applying longitudinal tension in the cathode from atmospheric pressure applied to the bellows.

15. An electron discharge device comprising a sealed envelope having a filamentary cathode therein, means securing said cathode at one part thereof, means having tensioning engagement at to the second mentioned said means, said member having a differential of pressure applied on opposite sides thereof and maintaining a flexing moment on said flexible member and said flexible member thereby continuously exerting a slidin moment to said second mentioned means and thereby a constant tension to said portion of the cathode.

16. An electron discharge device comprising a sealed and evacuated envelope having a filamentary cathode therein, means securing said cathode at one part thereof, a second means having tensioning engagement at another part of said cathode holding taut the intervening portion of said cathode between the two said means, and a flexible member having one side exposed to the evacuated interior of said envelope and an opposite side exposed to the exterior atmosphere thereby maintaining a flexing momentvon said flexible member, said flexible member being responsive to said flexing moment and said flexible member being in engagement at its said side interior of the envelope with said second means wherebyinward deformation of said flexible member exerts acontinuous moment of force on said second means by excess of atmospheric pressure exterior of the envelope over the lesser interior pressure resulting from evacuation of the envelope and whereby the inward deformation of said flexible member moves the said second means in the 8 direction of tensioning of the said cathode por' tion.

17. An electron discharge device comprising a sealed and evacuated envelope having a filamentary cathode, providing a leg and a bight, means securing said leg in fixed position in said envelope, a second means having supporting engagement with said cathode under the said bight thereof, and means including a part exposed exterior to said envelope and to the atmosphere and movable under influence of differential of interior and exterior pressures and the last said means having tension-applying connection with the second means whereby the leg of the cathode is tensioned by atmospheric pressure.

EDMUND G. SHOWER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,167,201 Dallenbach July 25, 1939 2,229,957 Crawford Jan. 28, 1941 2,399,004 Crawford Apr. 23, 1946 2,420,560 Ramo May 13, 1947 2,434,529 Werner Jan. 13, 1948 2,441,349 Eitel et a1. May 11, 1948 2,475,646 Spencer July 12, 1949 

